Oil tank water drainer



Jan. 20, 1953 F. HENIGMAN OIL TANK WATER DRAINER Filed Sept. 29, 1950Inventor AIM/may Patented Jan. 20, 1953 UNITED STATES PATENT OFFICE OILTANK WATER DRAINER Frank Henigman, Chicago, Ill.

Application September 29, 1950, Serial No. 187,641

3 Claims.

This invention relates to a water drainer attachment for oil tanks suchas stock tanks or oil storage tanks of the type used in crude oilproduction fields and has for its primary object to provide a drainagetank of extremely simple construction which may be quickly and easilyattached to a storage tank for oil and arranged so that any watercontained in the oil will be separated therefrom and fiow by gravityinto the drainage tank from which the water can be removed without lossof any of the oil from the storage tank.

Another object of the invention is to provide a drainage tank havingmeans for visually indicating the amount of water therein and foradditionally indicating whether or not all of the water has been drainedfrom the storage tank which is connected to the drainage tank.

A further object of the invention is to provide a drainage tank fromwhich water is adapted to be drained from adjacent the bottom thereofthrough the top of the drainage tank by the pressure of the oil in thestorage tank with the drainage of the water from the drainage tank beingunder the control of an operator having available a visual indication atall times of the water level in the drainage tank to prevent drainingoff any of the oil while accomplishing the draining off of water.

Still'a further object of the invention is to provide a drainage devicefor storage tanks which will prevent the accumulation of water in thebottom of a storage tank and the resulting damage to the storage tankbottom and which will additionally function efiectively to prevent aloss 'of oil in connection with the draining off of water from a storageor stock tank.

Various other objects and advantages of the invention will hereinafterbecome more fully apparent from the following description of thedrawing, illustrating presently preferred embodiments thereof, andwherein:

' be of any conventional construction usually ineluding an outlet nipple6 in a side wall thereof and adjacent its bottom which is normallyclosed I by a cap I, which is threaded to the outer end thereof. The.top of the tank is ordinarily provided with a filling port 8, normallyclosed by a plug 9, when not in use, and may be provided with aconventional air vent iii for venting the tank while oil is beingdrained therefrom and for facilitating the venting of the tank fordraining off water from the bottom thereof, as will hereinafter becomeapparent. The tank bottom I I is provided with an internally threadedport I2 and the side wall thereof, adjacent the bottom H and near theport [2 is provided with a similar internally threaded port IS. Theports 12 and I3 constitute conventional parts of the tank 5 and areemployed in the draining off of water from the bottom part of the tank.The parts 6 to l3, inclusive of the tank 5, as illustrated in Figure 1and as briefly described are all of conventional construction and formno part of the present invention.

The water drainer unit, designated generally l4 and comprising theinvention includes a relatively small tank l5 which is adapted to be disposed preferably with the top thereof slightly beneath the level of thetank bottom ll, so that if the tank bottom H is resting on the groundthe drainage tank It will ordinarily be disposed in a pit l6 and thusslightly below the ground level, as illustrated in Figure 1. The top I!of the tank l5 may be welded to the side wall of the tank and thuspermanently secured thereto or said tank top ll may be detachablysecured to the side wall of the tank by detachable fastenings, notillustrated in Figure l. I? is provided with an external nipple l8through which a vertical portion I9 of a drain pipe 20 extends. Thelower end of the drain pipe portion l9 opens adjacent the bottom of thedrain tank l5, as seen in Figure 1, and the drain pipe 2!], above thetop of the tank l5 has a horizontally disposed portion extending awayfrom the tank IS the opposite end of which, not shown, is adapted toopen at any suitable drainage point. Said horizontal portion of thedrain pipe 26 is provided with a manually controlled shutofi valve 2|.

A conduit 22 has one end threadedly engaging in the boss l2 and incommunication with the interior of the bottom portion of the tank 5 andthe opposite end of said conduit 22, which is disposed at an angle tothefirst mentioned end, is connected to a boss 23 of the drain tank [5 andopens into said drain tank between the top and bottom thereof butpreferably nearer to the top I! than to the bottom of the tank 15. Theconduit 22 includes an elbow joint 24 by which its angularly disposedend portions are connected.

The top wall A conduit, designated generally 25, includes a pipe 26which is preferably transparent and which has one end threadedlyengaging the boss I3 and opening into the tank 5 above and adjacent thetank bottom H. Conduit 25 includes a pipe 21 which is disposed at anangle to the pipe 26 and has one end connected to a boss 28, formed inthe top wall I! of the tank I5 and which opens into the top of thedrainage tank I5. The opposite, adjacent ends of the pipes 26 and 21 areconnected by an elbow coupling 29.

A pair of elbow couplings 30 are tapped into the side wall of thedrainage tank I5, one adjacent the top and the other adjacent the bottomthereof and in vertical alignment. A sight tube 3| of a transparentmaterial is interposed between and connected at its ends to thecouplings 30 and through said couplings is in communication with thedrainage tank I5 adjacent its top and bottom.

'The drainage tank I5 is provided in its side wall and adjacent itsbottom 32 with a port 33, formed by an externally disposed internallythreaded boss and said port 33 is normally closed by a threaded plug 34.

Figure 2 illustrates a slightly modified form of the drainage tank,designated generally I5a and which difiers from the drainage tank I5only in that its top wall I'Ia may be formed integral with the side wallof the tank |5a and is provided with an integral relatively largeupstanding neck 35 having an annular external flange 35 at its upperend. A cover plate 31 is disposed over and closes the upper end of theneck 35 and is detachably secured thereto by nut and bolt or othersuitable fastenings 38 so that the cover plate 31 may be removed forcleaning the interior of the drainage tank.

From the foregoing it will be readily apparent that any water containedin the oil 39 which fills or partially fills the storage tank 5 willsettle to the bottom of said tank and will thus find its way to thedrain conduit 22 through which it will flow by gravity into the draintank I5. Unless there is suificient water to fill the drain tank I5, itwill be readily apparent that some of the oil 39 will also flow bygravity into the drain tank I5, since it is below the level of thestorage tank 5 so that the tank I5 will always be filled ordinarily,partly with water and partly oil. Due

to the greater specific gravity of the water, the

water will be disposed in the tank I5 below the oil 39 and in Figure lthe water has been indicated at 40. It will be readily apparent thatthis water level will be visually indicated by the sight tube 3| inwhich the water level 40 will correspond to the water level in thedrainage tank, oil filling the upper portion of the sight tube. Asadditional water settles to the bottom of the tank 5 and finds its waythrough the conduit 22 to the drain tank I5, the level of the water 40will rise in the tank I5 causing a part of the oil 39 to be forced backfrom the tank I5 through the conduit 25 into the tank 5 until,eventually, if the water is not drained off of the tank i5 it will fillthe conduit 25 and be visible in its transparent portion 26. However,ordinarily when the sight tube 3| indicates that the water level isrelatively high in the drainage tank I5 the operator will open the valve2| so that the pressure of the liquid in the tank 5 will force the wateroutwardly through the drain pipe 20. The operator by observing the fallof the water level in the tube 3| may shut the valve 2| before "thewater level falls below the open lower end of the pipe portion I9 toprevent any of the oil above the water from entering the pipe portion I9and be wasted by drainage. The upper conduit 25 allows the oil to returnmore rapidly to the tank 5 as water flows through the conduit 22 fromthe tank 5 to the drain tank I5 thus enabling the water level in thedrain tank to be established more rapidly. However, the drain unit I4will operate without the conduit 25 although less efficient since thewater would then have to flow to the drain tank I5 through said conduitand the oil 39 would also have to escape back through the conduit 22 tothe tank 5 to provide space for the additional water and this wouldprevent water accumulating in the tank I5 above the level of the conduit22 whereas with both conduits being employed, the entire tank I5 can befilled with water. The transparent conduit portion 26 enables anexperienced operator to accurately judge when the proper oil and waterlevel has been obtained and how much water needs to be drained off fromthe tank I5, by observing the flow of liquid between the drain tank I5and storage tank 5 through the conduit portion 256.

The dischar e port 33 may be employed in conjunction with conventionalautomatic drainage equipment, not illustrated, by connecting the port 33to such equipment by a swing joint, not shown, so that the drain tank I5may then operate automatically instead of by manual use of the valve 2|.

While the invention has been described for use with a storage tank foroil, it is to be un derstood that the drainage unit is equally welladapted for use for storage tanks containing other liquids having aspecific gravity less than the specific gravity of water, such asgasoline. Obviously the storage tank and drain tank may be made invarious sizes and shapes and it is not essential that the drainage tankbe disposed entirely below the level of the storage tank so long as itsbottom is sufiiciently below the level of the bottom of the storage tankso that the open lower end of the drainage tube portion I9 will likewisebe disposed below the level of the storage tank bottom.

Various other modifications and changes are contemplated and mayobviously be resorted to, without departing from the spirit or scope ofthe invention as hereinafter definedby the appended claims.

I claim as my invention:

1. The combination with a storage tank containing a liquid having aspecific gravity less than the specific gravity of water, of a waterdrainage unit for use with the storage tank comprising a drainage tankhaving a top wall disposed below the level of the storage tank bottom, afirst conduit having a lower end communitating with the drainage tanksubstantially above the drainage tank bottom and beneath the top of thedrainage tank, said first conduit havin an upper end communicating withthe storage tank adjacent its bottom, a second conduit having one endcommunicating with the top of the drainage tank and having an oppositeend opening into the storage tank above the upper end of the firstconduit, a drainage conduit having an inlet end disposed within thedrainage tank and opening adjacent the drainage tank bottom andsubstantially below the level of the lower end of the first conduit,said drainage tank being closed except for said conduits, said drainageconduit extending outwardly from the drainage tank and being disposedwith its uppermost portion adjacent the level of the bottom of thestorage tank, and control means for shutting off the flow of liquidthrough the drainage conduit, the water contained in the storage tankdraining therefrom by gravity through the first conduit to fill thebottom portion of the drainage tank and the remainder of the drainagetank will be filled with the other liquid of the storage tank to thecapacity of the drainage tank, the other liquid of the storage tankbeing forced back from the drainage tank to the storage tank throughsaid second conduit as the drainage tank fills with water, said controlmeans being opened for draining off the water from the drainage tank.

2. A drainage unit as in claim 1, said second conduit having atransparent portion for visually indicating the flow of liquidtherethrough and the type of liquid contained therein.

3. The combination with a storage tank containinga liquid having aspecific gravity less than the specific gravity of water, of a waterdrainage unit for use with the storage tank comprising a drainage tankhaving a top wall disposed at a level not above the level of the storagetank bottom, a first conduit having a, lower end communicating with thedrainage tank substantially above the drainage tank bottom and beneaththe top of the drainage tank, said first conduit having an upper endcommunicating with the storage tank adjacent its bottom, a secondconduit having one end communicating with the drainage tank above thelower end of said first conduit and having an opposite end opening intothe storage tank above the upper end of the first conduit, a drainageconduit having an inlet end disposed within the drainage tank andopening adjacent the drainage tank bottom and substantially below thelevel of the lower end of the first conduit, said drainage conduitextending outwardly from the drainage tank above the level of the inletend thereof, said drainage tank being closed except for said conduits,and control means for shutting off the flow of liquid through saiddrainage conduit, the water contained in the storage tank drainingtherefrom by gravity through the first conduit to fill the bottomportion of the drainage tank and the remainder of the drainage tankbeing filled with the other liquid of the storage tank to the capacityof the drainage tank, the other liquid of the storage tank being forcedback from the drainage tank to the storage tank throughsaid secondconduit as the drainage tank fills with water, said control means beingopened for draining off the water from the drainage tank.

FRANK HENIGMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 374,879 Pearson Dec. 13, 18871,530,087 MacArthur Mar. 17, 1925 1,613,507 Feely Jan. 4, 1927 1,722,160Smith July 23, 1929 FOREIGN PATENTS Number Country Date 174,548 GreatBritain Feb. 2, 1922

